The objective of the Confocal Microscopy Core Facility is to provide state-of-the-art instrumentation for examination of single living cells and tissues with submicron 3-dimensional resolution. The facility houses a Zeiss LSM 510 laser scanning confocal microscope equipped with multiple lasers to provide a variety of excitation lines. A tunable pulsed Ti:Sapphire laser (700-900 nm) provides 200 femtosecond pulses for two and three-photon excitation of a variety of fluorophores whose one-photon excitation cross sections are in the ultra violet and visible light spectrum. The facility is open 7 days per week. Time on the instrument is by reservation only, and Cancer Center members will always have priority over nonmembers. The Facility Director will have overall responsibility for the operations of the facility and will provide expertise and consultation to core users in live cell confocal and multiphoton imaging. The Facility Manager has day-to-day responsibility for the microscopy component of the facility under the supervision of the Director. An Advisory Committee, appointed by the Cancer Center, meets semi-annually, addressing the facility operations, new technology development, and setting of policy. The Advisory Committee will report to the Senior Leaders Committee of the Cancer Center. The Confocal Microscopy Core will have a large and positive impact on the Cancer Center Scientific Programs. In addition, the anticipated heavy use of the facility among different departments and centers will foster productive interactions between individual investigators to promote new collaborations.